M&S says

Ideal for enhancing a bedroom design aesthetically and hiding unwanted quirks of bed furniture, adding a valance can complete a room both in looks and in practical terms. Our pure Egyptian cotton valance not only looks fantastic and comes in an array of colours, but possesses the best qualities of excellent durability, gentle softness, and real convenience, being Non Iron. The fine quality Egyptian cotton is known around the globe as one of the best cottons, and with our added StayNEW™ technology to keep it looking fresh, this is fabulous long-lasting luxury bed linen.